To-date several publications have presented suggestions that diseased potato tubers appear to contain substances which act as teratogenic agents, causing spina bifida and anencephaly in humans. The hypothesis implied that the proposed teratogenic agents were either present in potato tubers resistant to plant diseases or synthesized as a defense mechanism when the tubers were mechanically injured or infected with a disease organism. The objectives are to determine if potato tubers infected with the blight organism Alternaria solani and other pathogenic organisms can induce abnormalities in the offspring from marmosets fed on a partial diet of the diseased tuber tissue, to conduct feeding studies with pregnant laboratory animals other than the marmoset in an attempt to find a more suitable bioassay for possible induced fetal abnormalities by the metabolites resulting from potato disease, to isolate specific groups of chemical compounds from the diseased tubers which will be fed to laboratory animals, to determine if the disease organisms or the metabolites from the organism can be responsible for inducing fetal abnormalities, and to determine if disease resistant potatoes being selected as potential new variety releases, contain quantities of specific chemicals which may have detrimental effects on developing fetuses when ingested by the mother. The method of approach will be to feed blighted tuber tissue and chemical fractions from diseased tuber tissue, healthy tuber tissue and the disease organism to marmosets and other laboratory animals, by incorporating the diseased material into the diet and by stomach tube feeding. Standard biochemical procedures will be used for the isolation and identification of materials fed to the assay animals. All test animals will be evaluated for all observable abnormalities in the pregnant animal and its offspring.